Effects of Transgenic Cotton-Based Cropping Systems and Their Fertility Levels on Succeeding Wheat Crop

Cotton–wheat is the second most important cropping system after rice–wheat in India and Pakistan, and is practiced on about 4.02 mha. By 2010, more than 6 million Indian farmers had adopted transgenic Bt cotton on 9.4 mha—almost 90% of the country’s total cotton area. There is a paucity of information on the effects of intercropping and integrated nitrogen (N)–management practices in transgenic Bt cotton on productivity, nutrient availability, and soil biological properties in the succeeding wheat crop in a cotton–wheat system. A study was made to evaluate and quantify the residual effect of two-tiered intercropping of cotton and groundnut with substitution of 25–50% recommended dose of nitrogen (RDN) of cotton by farmyard manure (FYM) on productivity and soil fertility in a cotton–wheat system at New Delhi during 2006–2008. Wheat following groundnut-intercropped cotton receiving 50% RDN substitution through FYM had significantly 5% greater grain yield than that after sole cotton. Residual soil fertility in terms of organic carbon (C), potassium permanganate (KMnO₄)-N, and dehydrogenase activity (14%) showed an improvement under cotton + groundnut–wheat system with substitution of 50% RDN of cotton by FYM. Apparent N balance as well as actual change in KMnO₄-N at wheat harvest was negative in most of the treatments, with greater loss (–58.1) noticed under pure stand of the cotton–wheat system with 100% RDN of cotton through urea. The study suggested that inclusion of legume and organic manure in transgenic Bt-cotton–wheat system is a sustainable practice for combating escalating prices of N fertilizers with environmental issues and instability of transgenic hybrids in south Asian countries.     

Effect of nutrient‐management practices on growth,fruiting pattern,and yield of Asiatic cotton (Gossypium arboreum L.)

Asiatic cotton (Gossypium arboreum) is mostly grown in the rainfed regions of India. However, little is known about the effects of nutrient‐management practices on plant growth and fruiting pattern of Asiatic cotton. Therefore, plant growth and fruiting pattern under four nutrient‐management treatments, N, NPK, FYM (10 Mg ha^–1), and INM (integrated nutrient management: a combination of NPK and FYM) were quantified during 2000–01 to 2002–03 (years 16 to 18 of a long‐term field experiment). Plants of the INM and FYM treatments were taller (68.4–149.5 cm) and had more main stem nodes per plant (30.5–44.5) as compared to N and NPK treatments. In treatment N, the shortest plants (50.9–83.6 cm) and the least number of fruiting structures were produced. Plants of the INM and FYM treatments accumulated more squares and bolls. Maximum boll production was 10–19 days earlier with the manure‐amended than the N and NPK treatments. Treatment N had the lowest seed cotton yield (639–790 kg ha^–1), because of small boll size (1.48–1.73 g) and few open bolls. Seed cotton yield followed the trend: NPK (815–1278 kg ha^–1) < INM (776–1551 kg ha^–1) < FYM (902–1593 kg ha^–1). Water stress and nutrient deficiencies (P and Zn in the N and Zn in the NPK treatments) as a consequence of nutrient depletion over the years may have decreased seed cotton yields in treatments that received mineral fertilizer alone in comparison with manure‐amended treatments. On a long‐term basis, FYM application should therefore form an integral part of nutrient recommendation.     

Intercropping and balanced nutrient management for sustainable cotton production

The productivity of cotton is lowest in India and far below that of the world average productivity. Suitable management practices like intercropping and judicious combination of organic and inorganic manures are considered as yield improvement technologies and can avoid environmental pollution. However, which intercrop is suitable for the study area and what combination of nutrients will perform better needs to be investiaged. With this background and to test-verify the same, field experiments were conducted on cotton with split plot design to evaluate cotton based intercropping system along with nutrient management practices for enhancing the cotton productivity. Five intercropping systems viz., sole cotton, cotton + onion, cotton + blackgram, cotton + greengram and cotton + lucerne were included in the main plot. The subplot consisted of combinations of inorganic and organic manures namely, 100% recommended inorganic nitrogen (N), 75% inorganic N + 25% N through poultry manure, 75% inorganic N + 25% N through sunnhemp, 75% inorganic N + 25% N through farm wastes, 75% inorganic N + 25% N through weed compost. The results revealed that sole cotton followed by cotton + blackgram intercropping and 75% inorganic N + 25% N through poultry manure recorded better growth and yield attributes, higher cotton yield during both the years. Cotton + onion resulted in the maximum cotton equivalent yield of 2396 kg ha^?1 followed by cotton + blackgram (2240 kg ha^?1). Better N use efficiency and post-harvest soil available N, phosphorus (P) and potassium (K) was also associated with cotton + blackgram intercropping and 75% inorganic N + 25% N through poultry manure. Benefit: cost (BC) ratios were also higher in the same treatment. It could be concluded from these results that the cotton productivity is higher under the sole crop of cotton, however, the cotton equivalent yield is significantly higher with intercropping and these treatments proved that soil fertility status can be sustained with integrated plant nutrient management practices and intercropping systems.     

Symbiotic parameters,growth, nutrient accumulation,productivity and profitability as influenced by integrated nutrient management in lentil (Lens culinaris)

Field experiments evaluated the effects of integrated nutrient management on symbiotic parameters, growth, nutrient accumulation, productivity and profitability of lentil (Lens culinaris Medikus). Application of recommended dose of nutrients (RDN, 12.5 kg N ha^?1 + 40 kg P₂O₅ ha^?1) + 25 kg ZnSO₄ ha^?1 + seed inoculation with biofertilizers [Rhizobium + phosphate solubilizing bacteria (PSB) + plant growth promoting rhizobacteria (PGPR)] + 1.0 g ammonium molybdate kg^?1 seed recorded the highest number & dry weight of nodules, leghaemoglobin content, root & shoot dry weight, plant height, number of pods plant^?1 and 100-seed weight. The next best treatment was RDN + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg^?1 seed. On the basis of mean of three-year data, the treatment of RDN + 25 kg ZnSO₄ ha^?1 + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg^?1 seed proved the best in realizing the highest grain yield (34.0%), gross returns (34.0%) and net returns (54.8% higher over control). Nitrogen, phosphorus and potassium in the grains and straw were significantly improved where RDN was applied in combination with seed inoculation, basal application of ZnSO₄ and seed treatment with 1 g ammonium molybdate than their single applications.     

Nutrient Utilization Indices of NPK and Drought Management in Groundnut under Sandy Soil Conditions

ABSTRACT

In arid zones, farmers are obligated to reduce water amounts used in irrigating their lands. Consequently, reduction in final yields is realized. Thus, dealing with such a case became a decisive act. We tried to investigate the acceptable degree of lowering irrigation water with sustaining the productivity of groundnut as a way for managing drought conditions. Therefore, in summer seasons of 2016 and 2017 at the Experimental Research and Production Station, National Research Centre, Egypt, field trials were conducted with growing groundnut plants under three irrigation levels, i.e., 50%, 75%, and 100% of crop evapotranspiration (ET_c), denoted as I₅₀, I₇₅, and I₁₀₀, respectively. N, P, and K contents in seed and shoot and their yields in addition to harvest and partitioning indices were estimated. In spite of irrigating groundnut plants by normal water amounts, I₁₀₀, caused the maximum weight of seed biomass yield ha?1 and seed N and P contents, I75 was similar to I₁₀₀ for producing shoot biomass yield ha?1 and seed K content. Moreover, N and P yields (for shoots and seeds) and k yield (for seeds) showed the maximum values with I₁₀₀. Differences in all nutrient harvest indices (NHI, PHI, and KHI) between I₁₀₀ and I75 were not significant. Furthermore, I75 statistically leveled with I₁₀₀ in nutrient partitioning indices, viz., NPI, PPI, and KPI. In conclusion, groundnut straw residues produced by 25% less water supply than normal may share in managing drought stress by releasing nutrients and saving irrigation water in arid areas.     

Productivity,Quality and Soil Health as Influenced by Organic,Inorganic and Biofertilizer on Field Pea in Eastern Himalaya

A field experiment was conducted during two consecutive years of 2010–2011 and 2011–2012 to study the effect of biofertilizers in conjunction with organic and inorganic sources of nutrient management on productivity, quality and soil health on field pea at ICAR RC for NEH Region, Nagaland Centre Jharnapani, Nagaland, India. The experiment was laid out in split plot design with five nutrient sources in main plots and four treatment of biofertilizers with zinc in sub plots. Results indicated that the application of 100% recommended dose of fertilizer (RDF) through inorganic + 50% recommended dose of nitrogen (RDN) through vermicompost significantly improved root nitrogen (N) content, cation exchange capacity (CEC) of roots, NA activates, seed yield (1153 and 1262 kg ha^?1), straw yield (2182 and 2332 kg ha^?1) in the year of 2010–2011 and 2011–2012, respectively. Nutrients (N, P, K, S and Zn) uptake by seed and straw, protein content, protein harvest, soil organic carbon (SOC), available N, P, K, S, Zn and economics significantly higher with 100% RDF through inorganic + 50% RDN through vermicompost during both the years. Seed inoculation with biofertilizers along with 5 kg Zn ha^?1 markedly enhanced the root N content, CEC of roots, nitrogenase activities (NA), seed yield (1080 and 1193 kg ha^?1), straw yield (1978 and 2128 kg ha^?1), nutrients [N, phosphorus (P), potassium (K), sulfur (S) and zinc (Zn)] uptake, soil organic carbon (SOC) (%), and available N, P, K, S, and Zn of pea in both the years, respectively. These sources also give more income and benefit cost ratio per rupees invested.     

Effect of Soil and Nutrient-Management Treatments on Soil Quality Indices under Cotton-Based Production System in Rainfed Semi-arid Tropical Vertisol

Rainfed semi-arid tropical Vertisols of the Indian subcontinent encounter many problems on account of the physical, chemical, and biological soil qualities and consequently have poor crop yields. To ensure sustainable crop production, there is a need to improve and periodically assess the quality of these soils by adopting suitable soil and nutrient-management practices on a long-term basis. Hence, soil quality assessment studies were conducted at the Central Research Institute for Dryland Agriculture, Hyderabad, India, by adopting an ongoing long-term experiment from Akola Centre (Maharashtra) of All-India Coordinated Research Project for Dryland Agriculture (AICRPDA) for the rainfed Vertisol. This long-term experiment was initiated in 1987 with six soil and nutrient management treatments: T1, control; T2, 50 kg nitrogen (N) + 25 kg phosphorus pentoxide (P₂O₅) ha^?1; T3, 25 kg N ha^?1 through leuceana; T4, 25 kg N ha^?1 through farmyard manure (FYM); T5, 25 kg N + 25 kg P₂O₅ + 25 kg N ha^?1 through FYM; and T6, 25 kg P₂O₅ ha^?1 + 50 kg N ha^?1 through leuceana under cotton + greengram intercropping (1:1). Out of the 19 soil quality parameters studied, significant influence of the soil and nutrient-management treatments was observed on almost all the parameters except exchangeable calcium (Ca), available iron (Fe), labile carbon (LC), and bulk density (BD). A standard methodology using principal component analysis (PCA) and linear scoring technique (LST) was adopted to identify the key indicators and for computation of soil quality indices. The various key soil quality indicators identified for these Vertisols under cotton + green gram system were pH, electrical conductivity (EC), organic carbon (OC), available K, exchangeable magnesium (Mg), dehydrogenase assay (DHA), and microbial biomass carbon (MBC). The soil quality indices as influenced by different long-term soil and nutrient-management treatments varied from 1.46 to 2.10. Among the treatments, the conjunctive use of 25 kg P₂O₅ ha^?1 + 50 kg N ha^?1 through leuceana green biomass (T6) maintained significantly higher soil quality index with a value of 2.10 followed by use of 25 kg N + 25 kg P₂O₅ + 25 kg N ha^?1 through FYM (T5) (2.01). The order of percent contribution of these identified indicators to soil quality indices was OC (28%) > MBC (25%) > available K (24%) > EC (7%) > pH (6%) = DHA (6%) > exchangeable Mg (4%). Thus, the findings of the present study could be of immense use to the researchers, land managers, farmers, nongovernment organizations (NGOs) and other stakeholders for making periodical assessment of key indicators of soil quality, identifying the best soil and nutrient-management treatments and practices, and planning for improving soil quality to achieve higher productivity goals on a sustainable basis in rainfed semi-arid tropical Vertisol regions. The methodology of the study could also be useful for other rainfed semi-arid tropical Vertisol regions of the world.     

Soil nutrient status,yield and quality of lemon (Citrus limon Burm.) cv. ‘Assam lemon’ as influenced by bio-fertilizers,organics and inorganic fertilizers

An experiment was conducted at Mizoram University, Aizawl, India during 2015-2017 to study the effect of integrated nutrient management on yield and quality of lemon cv. ‘Assam lemon’ (Citrus limon Burm.). The experiment was comprised of nine treatments viz. T1: 100% recommended dose of fertilizers (RDF) through inorganic fertilizers (IF); T2: 100% N through Farm Yard Manure (FYM); T3: 75% N through FYM + 25% through IF; T4: 50% N through FYM + 50% through IF; T5:75% N through FYM +25% through IF + Azotobacter + phosphate solubilizing bacteria (PSB)+ potash solubilizing bacteria (KSB); T6: 50% N through FYM + 50% through IF+ Azotobacter + PSB?+?KSB; T7: 75% N through FYM + 25% through IF?+?Azospirillum + AMF?+?KSB; T8: 50% N through FYM + 50% through IF+ Azospirillum + arbuscular mychorrhizal fungi (AMF) + KSB; T9: control. Among all treatments, T5 recorded highest value with respect to growth, yield and soil quality. While, T7 showed superiority in quality characters.     

不同棉花间作模式中作物养分吸收和利用对间作优势的贡献

棉花间作能够解决棉花与粮食作物和蔬菜作物争地的矛盾,但是否有间作优势以及间作优势的作物营养基础是众所关心的问题。本研究在新疆石河子大学试验站设置棉花与花生、大豆、鹰嘴豆、洋葱、萝卜、线辣椒间作以及各个作物单作的田间试验,以期揭示以棉花为基础的间作体系的间作优势以及养分吸收和利用效率对间作优势的贡献。结果表明,棉花与鹰嘴豆、花生、洋葱、萝卜间作体系作物的吸氮量明显高于单作18%~74%,棉花与大豆和线辣椒间作体系作物的吸氮量低于单作10%和34%;棉花与大豆、鹰嘴豆、花生、洋葱、萝卜间作体系中作物吸磷量比单作增加5%~104%,棉花与线辣椒间作体系作物的吸磷量低于单作6%;棉花与花生、洋葱、萝卜间作体系中作物吸钾量高于单作20%~58%,棉花与大豆、鹰嘴豆和线辣椒间作作物吸钾量低于间作19%~22%。棉花与鹰嘴豆、花生、洋葱、萝卜间作以后土地当量比(LER)分别为1.02、1.30、1.12、1.68,都大于1,说明具有间作优势;棉花与大豆、线辣椒间作后LER分别为0.91和0.99,小于1,没有间作优势。棉花与花生、洋葱和萝卜间作体系氮磷钾吸收效率对LER的贡献分别为0.41~0.82、0.25~1.04和0.15~0.59,利用效率的贡献分别为0.35~0.04、0.03~0.14和0.16~0.01。结果表明,棉花与其他作物的间作优势在营养方面的基础主要来自于间作相对于单作吸收效率的增加,而不是利用效率的改变。     

Productivity,nutrient uptake and post-harvest soil fertility as influenced by cotton-based cropping system with integrated nutrient management practices in semi-arid tropics

Field experiments were conducted on cotton to evaluate the different cotton-based intercropping system along with balanced nutrient management practices on enhancing cotton productivity. Cropping systems have been considered as main plots and nutrient management practices have been considered as subplots. The results showed that cotton + onion system recorded the highest cotton equivalent yield (CEY) of 2052 and 1895 kg ha^?1 which was on par with cotton intercropped with dhaincha, which recorded 2010 and 1894 kg of CEY ha^?1 in both the seasons. Combined application of 100% recommended NPK with bioinoculants (S₅) registered highest CEY in both the seasons. Cotton intercropped with dhaincha (M₂) recorded highest uptake of N, P, and K. Among the nutrient management practices, application of 100% recommended NPK with bioinoculants (S₅) showed highest uptake of N, P, and K. A similar trend was noticed in the post-harvest soil fertility too and it is significantly higher under cotton + dhaincha and application of 100% recommended NPK with bioinoculants treatment compared to 100% recommend NPK alone. It could be concluded from these results that crop productivity can be improved and soil fertility status can be sustained with integrated plant nutrient management practices.     

Nutrient management effects on organic carbon pools in a sandy loam soil under rice-wheat cropping

Agricultural management practices are known to influence soil organic C. While changes in total organic C (TOC) are relatively less discernible over short to medium-term, some extractable pools of TOC are considered early indicators of changes in TOC. Therefore, to devise nutrient management practices that can lead to C sequestration, it is important to study their effect on soil organic C pools that may respond rapidly to management. We studied the impact of balanced (NPK) and imbalanced (N, NP, NK and PK) application of fertilizer nutrients without and with farmyard manure (FYM) on total and labile pools of organic C viz. water soluble (WEOC), potassium permanganate oxidizable (KMnO₄-C), microbial biomass (MBC) and fractions of decreasing oxidizability after 5-cycles of rice-wheat cropping. Integrated use of NPK and FYM significantly increased TOC and extractable C pools in both surface (0–7.5 cm) and sub-surface (7.5–15 cm) soil. Majority of TOC (72%) was stabilized in less labile and recalcitrant fractions; the magnitude being higher under balanced (NPK+FYM) than imbalanced nutrient management (N+FYM). The results showed that balanced fertilizer application conjointly with FYM besides enlarging TOC pool favorably impacts soil organic matter composition under rice-wheat system.     

Influence of integrated nutrient management (INM) on nutrient use efficiency,soil fertility and productivity of hybrid rice

A field experiment was conducted during the two consecutive kharif seasons of 2011 and 2012 on sandy-loam lateritic soil of Indian subtropics to investigate the impact of integrated nutrient management (INM) on crop productivity, nutrient use efficiency of applied nutrients and soil fertility in restoring sustainability with hybrid rice cultivation. Application of 50% recommended dose of fertilizer (RDF) + 50% recommended dose of nitrogen (RDN) through mustard oil cake (MOC) or 75% RDF + 25% RDN through MOC + biofertilizer recorded significantly higher grain and biomass yields, greater NPK removal and higher partial factor productivity of applied nutrient (PFPN) than those of the crop having 100% RDF, 100% RDN through MOC and 25% RDF + 75% RDN through MOC, which showed very poor performance. The former treatments also improved organic carbon and available NPK contents in soil in spite of greater removal of NPK by the crop. Results of study suggested integrated use of 50% RDF + 50% RDN through MOC or 75% RDF + 25% RDN through MOC + biofertilizer for increasing hybrid rice productivity, PFPN and improving soil fertility for sustainability.     

Plant and Soil Responses to the Combined Application of Organic Amendments and Inorganic Fertilizers in Degraded Sodic Soils of Indo-Gangetic Plains

ABSTRACT

Soil degradation due to salinization and sodication is the paramount threat in Indo-Gangetic plains. The studies on reclamation and management of such soils can provide a pragmatic solution for improving fertility and productivity of these soils. Lack of organic matter and poor availability of nutrients are the major factors for low productivity of sodic soils. Rice-wheat is a major cropping system in Indo-Gangetic alluvial plain region even in reclaimed sodic soils and farmers used inorganic fertilizers only to get higher yields. In this study, we used different organic sources of amendments in conjunction with different nitrogen (N) doses supplied through inorganic fertilizers to investigate the combined effect of organic and inorganic amendments on soil fertility and the productivity of rice- wheat system in sodic soils. Salt tolerant varieties of rice and wheat were grown in sodic soil (pH: 9.30, EC: 1.12 dSm^?1 and exchangeable sodium percentage, ESP: 52) during 2014–15 to 2016–17 in a field experiment with 13 treatment combinations of organic and inorganic amendments (T₁- (control) 100% of recommended dose of N (RDN), T₂-municipal solid waste compost (MSWC) @10 t ha^?1 + 50%RDN, T₃- MSWC @10 t ha^?1 + 75% RDN,T₄- MSWC @10 t ha^?1 + 100%RDN, T₅-Vermicompost (VC) @10 t ha^?1 + 50% RDN, T₆- VC @10 t ha^?1 + 75% RDN, T₇-VC@10 t ha^?1 + 100% RDN, T₈- Farm yard manure (FYM) @ 10 t ha^?1 + 50% RDN,T₉- FYM@10 t ha^?1 + 75%RDN, T₁₀- FYM@10 t ha^?1 + 100% RDN, T₁₁-Pressmud (PM) @10 t ha^?1 + 50% RDN, T₁₂-PM@10 t ha^?1 + 75%RDN, and T₁₃- PM @ 10 t ha^?1 + 100% RDN). Use of organic amendments supplemented with reduced dose of N through inorganic fertilizer has significantly improved soil bio-physical and chemical properties. Application of VC@10 t ha^?1 + 100% RDN (T₇) decreased soil bulk density, pH, EC, ESP and Na content to 2.0, 4.2, 26.5, 42.8, and 56.6% respectively and increased soil organic carbon by 34.6% over control (T₁). Soil fertility in terms of available N, P, K, Ca, and Mg increased by 20.5, 33.0, 36.4, and 44%, respectively, over control (T₁). Soil microbial biomass carbon, nitrogen, and phosphorus also improved significantly due to combined use of organic amendments and inorganic fertilizers over the only use of inorganic fertilizers. Decreasing in soil sodicity and increasing soil fertility showed significant increase (P < 0.05) in crop growth, growth indices, and grain yields of rice and wheat. The study revealed that combined use of VC or MSW compost @10 t ha^?1 in conjunction with 75% RDN through inorganic fertilizers in sodic soils proved sustainable technology for restoration of degraded sodic soils and improving crop productivity.     

Long‐term effects of organic manure and manufactured fertilizer additions on soil quality and sustainable productivity of finger millet under a finger millet–groundnut cropping system in southern India

In a 20‐yr‐old long‐term experiment, the impact of continuous application of organic manures and inorganic fertilizers on soil quality and the sustainability of finger millet production was conducted on two cropping systems: finger millet and finger millet–groundnut on an Alfisol of semi‐arid southern India. The study was conducted from 1992 to 2011 at the All India Coordinated Research Project for Dryland Agriculture, UAS, Bangalore, using a randomized block design. The treatments comprised of T₁: control [no fertilizer and no farmyard manure (FYM) applied], T₂: FYM 10 t/ha, T₃: FYM 10 t/ha + 50% of recommended NPK (50:50:25 kg/ha), T₄: FYM 10 t/ha + 100% of recommended NPK and T₅: 100% recommended NPK. Comparison of long‐term yield data between treatments was used to calculate a ‘sustainability yield index’ (SYI), which was greatest for T₄ (FYM 10 t/ha + 100% of recommended NPK), in both rotational (0.68) and monocropping (0.63) situations. Soil quality indices were determined using principal component analysis linear scoring functions. The key indicators which contributed to the soil quality index (SQI) under rotation were organic C; potentially available N; extractable P, K and S; exchangeable Ca and Mg; dehydrogenase activity and microbial biomass C and N. The largest SQI (7.29) was observed in T₄ (FYM 10 t/ha + 100% NPK), and the smallest (3.70) SQI was for the control. Application of 10 t/ha FYM together with NPK (50:50:25 kg/ha) sustained a mean yield of 3884 kg/ha.     

Effect of distillery effluents on plant and soil enzymatic activities and groundnut quality

A field experiment was conducted during the rainy season 2000 to examine the effect of distillery effluents, i.e., biomethanated spent wash (BSW), raw spent wash (RSW), and lagoon sludge (LS) versus recommended NPK+FYM (farmyard manure) on nutritional quality of groundnut (Arachis hypogaea L.) and enzyme activities of plant and soil. The distillery effluents did not affect the oil content (%), crude and true protein contents (%) in groundnut but increased the seed yield and the contents of methionine by 44 % (1.15 g (16 g N)^–1 vs. 0.80 g (16 g N)^–1 in control) and of cysteine by 24 % (1.36 g (16 g N)^–1 vs. 1.10 g (16 g N)^–1 in control). BSW produced the highest seed yield (619 kg ha^–1) followed by RSW (557 kg ha^–1) and LS (472 kg ha^–1). LS recorded the highest total chlorophyll content (2.94 mg (g FW)^–1) in groundnut leaves. Application of BSW and RSW significantly increased the activity of plant peroxidase whereas the plant polyphenol oxidase was higher in BSW only. The application of distillery effluents did not affect the nitrate reductase activity but BSW significantly increased the nitrate content in the rhizosphere soil. The three effluents significantly increased the dehydrogenase and alkaline phosphatase activity more than recommended NPK+FYM.     

Effect of Organic Manure and Crop Residue Based Long-Term Nutrient Management Systems on Soil Quality Changes under Sole Finger Millet (Eleusine coracana (L.) Gaertn.) and Groundnut (Arachis hypogaea L.) – Finger Millet Rotation in Rainfed Alfisol

A long-term experiment was conducted to evaluate the effect of integrated use of organic and inorganic sources of nutrients on soil quality and its relation to finger millet yield under two predominant crop rotations viz., groundnut–finger millet and finger millet monocropping in hot moist semiarid rainfed Alfisol soils in South India. Two experiments were laid out separately for each cropping system in a randomized complete block design with five treatments individually with FYM and maize residue-based combinations viz., Control (T1), FYM @ 10t ha ^?1 or Maize residue (MR) @ 5t ha ^?1 (T2), farm yard manure (FYM) @ 10t ha ^?1 or Maize residue (MR) @ 5t ha ^?1 + 50% RDF (Recommended Fertiliser Dose) N, P₂O₅ &; K₂O (T3), FYM @ 10t ha ^?1 or Maize residue (MR) @ 5t ha ^?1 + 100% RDF N,P₂O₅ &; K₂O (T4), Recommended N, P₂O₅ &; K₂O (T5). Thus, four sets of nutrient management systems were evaluated. The results showed that farm yard manure or maize residue application in combination with recommended dose of fertilizer significantly improved the soil physical, chemical, and biological properties compared to control and application of inorganic fertilizers alone. Based on evaluation of 19 soil quality parameters under each of the four nutrient management systems, the common key soil quality indicators emerged out were: organic C (OC), available nitrogen (N), available sulfur (S), and mean weight diameter (MWD) of soil aggregates. A significant correlation between the finger millet yield and the relative soil quality indices (RSQI) indicates the importance of soil quality in these semiarid Alfisol soils. The results and the methodology adopted in the present study could be of importance in improving the soil quality not only for the region of the study, but also in other identical soils and cropping systems across the world.     

Carbon and nutrient dynamics under long-term nutrient management in tropical rice-wheat-jute system

Impacts of 43-year nutrient management on carbon (C) and nutrient dynamics were studied in a rice-wheat-jute system in tropical India. Carbon dynamics was investigated on the basis of its distribution of labile (microbial biomass C, permanganate oxidizable C and water soluble C) and slow pools (Walkley Black oxidizable organic C), its indices (C pool index, lability index) and C management index (CMI) at different soil depths. Nutrient dynamics was judged by major nutrients availability, and related soil enzymatic activities. We studied seven treatments including unfertilized control, 100% NPK (N:P₂O₅:K₂O 60:30:60), 50% NPK, 150% NPK, 100% NP, 100% N, 100% NPK + farm yard manure (10 tonnes FYM ha^?1). Nutrients availability and soil enzymatic activities were significantly increased under balanced fertilization (100% NPK + FYM) over other treatments. Labile, slow and total C was also found highest in 100% NPK + FYM. Enhanced C indices under 100% NPK + FYM over 100% NPK and other treatments signified the importance of long term balanced fertilization on soil C stabilization. Lability indexes were lower at sub-soil (30-45cm). In terms of favourable nutrient dynamics and CMI, balanced application of NPK plus organics were recommend for long term sustainability of rice-wheat-jute system in tropics.     

Effects of Fertilizers on Yield,Sustainability, and Soil Fertility under Rainfed Pigeon pea + Rice System in Subhumid Oxisol Soils

A long-term field experiment was conducted at the research farm of the All-India Coordinated Research Project for Dryland Agriculture, Phulbani, Orissa, India, from 2001 to 2006 to identify the best integrated nutrient-use treatments for ensuring greater productivity, profitability, sustainability, and improved soil quality in pigeon pea + rice (two rows of pigeon pea followed by five rows of rice alternately) intercropping system. In all, nine treatments, eight comprising integrated nutrient-use practices, chemical fertilizer (CF), farmyard manure (FYM), and green leaf manure (GLM) to supply nitrogen (N) at 45 kg N ha^–1 and one farmer's practice equivalent to 25 kg N ha^–1 (FYM 5 t ha^–1), were tested on a long-term basis. Results of the study revealed that 20 kg N ha^–1 (FYM) + 25 kg N (CF) gave maximum mean rice grain yield of 1.52 t ha^–1, followed by 20 kg N (GLM) + 25 kg N (urea) with grain yield of 1.51 t ha^–1. In the case of pigeon pea, 30 kg N (FYM) +15 kg N (urea) gave maximum pigeon pea grain yield of 0.94 t ha^–1, which was 34% greater than the sole application of chemical fertilizer. Pigeon pea grain yield tended to increase with increasing proportion of organic N in FYM + CF or GLM + CF combinations. Application of 20 kg N (FYM) + 25 kg N (urea) recorded maximum mean rice equivalent yield of 3.59 t ha^–1 and sustainability yield index of 59%. While studying profitability, application of 20 kg N (FYM) + 25 kg N (CF) gave maximum net returns of US$168.94 ha^–1. Impact of treatments on soil quality as assessed in terms of relative soil quality indices (RSQI) increased with increasing proportion of organic sources of N. Using an innovative and new approach, an index of integrated productivity–sustainability–profitability–soil quality performance index (I _P,S,Pr,SQ) was computed to make a precise evaluation of the treatments. Based on this index, the order of performance of the treatments was T₆ [20 N (FYM) + 25 N (CF)] (7.7) > T₇ [30 N (FYM) + 15 N (CF) (6.9)] > T₃ [20 N (GL) + 25 N (CF)] (6.8) > T₅ [10 N (FYM) + 35 N (CF) (6.6)] > T₉ [GL] (6.5) > T₈ [CF] (6.2) > T₄ [30 N (GL) + 15 N (CF)] (6.0) > T₂ [10 N (GL) + 35 N (CF)] (5.7) > T₁ [FYM at 5 t ha^–1] (4.1). Thus, the results and the methodology adopted in this study using long-term data would be very useful to researchers, farmers, land managers, and other stakeholders not only in India but also across the world under similar climatic and edaphic situations.     

Nutrient Management for Sustaining Productivity of Sunflower-Based Cropping Sequence in Indian Semiarid Regions

A comprehensive long-term study (2006–2010) was undertaken to develop a balanced and integrated nutrient supply system for sunflower-based cropping sequence considering the efficient utilization of residual and cumulative soil nutrient balance along with added fertilizers by the crops grown in rotation. The fertilizer application was done in potato and sunflower while greengram was raised as such on their residual effect. Significant response in yield was observed with 150% of the recommended nitrogen, phosphorus and potassium (NPK) or inclusion of farmyard manure (FYM) with the recommended NPK in the cropping sequence indicating 6.2–7.0% gain in system productivity over the existing recommendations. Each additional unit of P and K nutrition prompted system productivity by 18.9 and 11.0 kg kg^?1 of applied nutrient, respectively. Apparent yield decline was observed in K and PK omission plots to the extent of 15.8 and 27.4% in potato, 10.5 and 23.9% in sunflower and 4.2 and 8.3% in greengram, respectively, compared to the recommended fertilization. The superiority of the FYM along with the recommended NPK (potato/sunflower) was evident on the overall profitability and sustainability of the system, highlighted by the significantly higher productivity (7.16 t SFEY ha^?1), sustainability yield index (SYI; 0.76), production efficiency (PE; 27.85 kg SFEY ha^?1 day^?1) and net returns (2520 USD ha^?1) with a B:C ratio of 2.91. Apparent change in potassium permanganate (KMnO₄)-N was negative in all the treatments while N and P balance was positive with 150% NPK fertilization. Nutrient uptake exceeded the replenishment with 100% NPK application and maintained net negative soil nutrient stock for all the primary nutrients, indicating the need for revalidation of the existing recommendations in the system perspective. Conspicuous improvement in residual soil fertility in terms of maximum buildup of soil organic carbon (14%) and enhancement in soil KMnO₄-N (4.2%), Olsen-P (19.4%), ammonium acetate (NH4OAc)-K (5.8%) and dehydrogenase enzyme activity (44.4%) was observed in FYM-treated plots over the initial values. The study suggested that the inclusion of legumes and FYM application with the recommended NPK in potato-sunflower cropping sequence will sustain the system’s productivity through the efficient use of nutrients, enhanced microbial activity and improved soil health while combating escalating prices of fertilizers as well as environmental issues in the Indo-Gangetic plains of India and similar environments.     

Dynamics of dry matter and nitrogen distribution in transplanted rice on mollisols

We studied the dynamics of dry matter (DM) and nitrogen (N) distribution in different plant parts (leaf, stem, and panicle) and grain yield of transplanted rice due to N management practices through neem coated urea (NCU). The results indicated that application of NCU at 125% recommended dose of N (RDN) with 50:25:25 split schedule at basal (B), active tillering (AT), and panicle initiation (PI) stages resulted in higher DM and N distribution to leaf, stem, and panicle at 60 and 90 days after transplanting and harvest than the application of prilled urea at 100% RDN with the same split schedule (existing practice). Further, the increment in grain yield was 10.95% than the existing practice. Hence, we suggest the application of NCU at 125% RDN with 50:25:25 split schedule at B, AT, and PI stages for achieving higher DM and grain yield on Mollisols.